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Metal ion

Jason S Kahn, Lina Freage, Natalie Enkin, Miguel Angel Aleman Garcia, Itamar Willner
The synthesis of nucleic acid-functionalized metal-organic frameworks (MOFs) is described. The metal-organic frameworks are loaded with a dye being locked in the structures by means of stimuli-responsive nucleic acid caps. The pH and K(+) -ion-triggered release, and switchable release, are demonstrated.
December 6, 2016: Advanced Materials
Ralf Kautenburger, Jonas M Sander, Christina Hein
For the safe long-term storage of high level radioactive waste (HLW), detailed information about geo-chemical behavior of radioactive and toxic metal ions under environmental conditions is important. Natural organic matter (NOM) can play a crucial role in the immobilization or mobilization of these metal ions due to its complexation and colloid formation tendency. In this study, the complexation of europium (as chemical homologue of trivalent actinides like americium) and uranium (as main component of HLW) by ten humic acids (HA) from different sources and Suwannee NOM river extract has been analyzed...
December 6, 2016: Electrophoresis
Makoto Kawatani, Makoto Muroi, Akira Wada, Gyo Inoue, Yushi Futamura, Harumi Aono, Kenshirou Shimizu, Takeshi Shimizu, Yasuhiro Igarashi, Naoko Takahashi-Ando, Hiroyuki Osada
Collismycin A (CMA), a microbial product, has anti-proliferative activity against cancer cells, but the mechanism of its action remains unknown. Here, we report the identification of the molecular target of CMA by ChemProteoBase, a proteome-based approach for drug target identification. ChemProteoBase profiling showed that CMA is closely clustered with di-2-pyridylketone 4,4-dimethyl-3-thiosemicarbazone, an iron chelator. CMA bound to both Fe(II) and Fe(III) ions and formed a 2:1 chelator-iron complex with a redox-inactive center...
December 6, 2016: Scientific Reports
Talal Mallah, Benjamin Cahier, Mauro Perfetti, Georges Zakhia, Daoud Naoufal, Fatima El-Khatib, Régis Guillot, Eric Rivière, Roberta Sessoli, Anne-Laure Barra, Nathalie Guihéry
The magnetic properties of the pentacoordinated [MII(Me4cyclam)N3]+ (Me4cyclam = tetramethylcyclam; N3 = azido and M = Ni and Co) complexes were investigated. Magnetization and EPR studies indicate that they possess an easy plane of magnetization with the axial anisotropy parameters D being close to 22 and larger than 30 cm-1 for the Ni and Co derivative, respectively. Ab initio calculations reproduce the experimental values of the zero field splitting parameters and allow determining the orientation of the anisotropy tensor axes with respect to the molecular frame...
December 6, 2016: Chemistry: a European Journal
Mohammadmahdi Etemadi, Saman Samadi, Shabnam Sharif Yazd, Pooya Jafari, Negin Yousefi, Majid Aliabadi
In the present study, a novel Cr(6+)-imprinted Pebax/chitosan/GO/APTES nanofibrous adsorbent (Cr(6+)-PCGA) was prepared and its performance was compared with PCGA nanofibers for selective sorption of Cr(VI) ions from aqueous solutions. The prepared nanofibers were characterized using FTIR, SEM and EDAX analysis. The influence of batch sorption experiments including GO/APTES content, pH, contact time, Cr(VI) initial concentration and temperature on the Cr(VI) sorption efficiency using synthesized nanofibers was investigated...
December 2, 2016: International Journal of Biological Macromolecules
G Karthiga Devi, K Sathish Kumar, R Parthiban, K Kalishwarlal
The present work reports the development of a Simple, rapid and eco-friendly route for the biosynthesis of gold and silver nanoparticles and their antimicrobial activity against gram positive and gram negative bacterial pathogens in the wound infected area. The synthesis was done using Mukia maderasapatna plant extract as a reducing agent. FT-IR analysis reported that the methanol extract was found to contain maximum number of functional groups which is responsible for the reduction of metal ions to metal nanoparticles...
December 2, 2016: Microbial Pathogenesis
Rajeev Kumar, Mohammad Oves, Talla Ameelbi, Naief H Al-Makishah, M A Barakat
In this work, chitosan (CS) functionalized polyaniline-polypyrrole (Pani-Ppy) copolymer (CS/Pani-Ppy) was synthesized applying a facile one pot method for the enhanced adsorption of Zn(II) and antimicrobial activity for E. coli and E. agglomerans. The synthesized materials were characterized using scanning electron microscopy, energy dispersive X-ray spectroscopy, Fourier transform inferred spectroscopy and X-ray photoelectron spectroscopy. The adsorption of the Zn(II) on the synthesized materials was highly dependent on the pH of the solution, the initial metal ion concentration, and temperature...
November 24, 2016: Journal of Colloid and Interface Science
Ting Zhang, Zhihong Tu, Guining Lu, Xingchun Duan, Xiaoyun Yi, Chuling Guo, Zhi Dang
Chicken eggshells (ES) as alkaline sorbent were immobilized in a fixed bed to remove typical heavy metals from acid mine drainage (AMD). The obtained breakthrough curves showed that the breakthrough time increased with increasing bed height, but decreased with increasing flow rate and increasing particle size. The Thomas model and bed depth service time model could accurately predict the bed dynamic behavior. At a bed height of 10 cm, a flow rate of 10 mL/min, and with ES particle sizes of 0.18-0.425 mm, for a multi-component heavy metal solution containing Cd(2+), Pb(2+) and Cu(2+), the ES capacities were found to be 1...
December 2, 2016: Journal of Environmental Management
Hyung-Seok Kim, John B Cook, Hao Lin, Jesse S Ko, Sarah H Tolbert, Vidvuds Ozolins, Bruce Dunn
The short charging times and high power capabilities associated with capacitive energy storage make this approach an attractive alternative to batteries. One limitation of electrochemical capacitors is their low energy density and for this reason, there is widespread interest in pseudocapacitive materials that use Faradaic reactions to store charge. One candidate pseudocapacitive material is orthorhombic MoO3 (α-MoO3), a layered compound with a high theoretical capacity for lithium (279 mA h g(-1) or 1,005 C g(-1))...
December 5, 2016: Nature Materials
Chun Li Liu, Qiu Ying Huang, Xiang Ru Meng
The synthesis of coordination polymers or metal-organic frameworks (MOFs) has attracted considerable interest owing to the interesting structures and potential applications of these compounds. It is still a challenge to predict the exact structures and compositions of the final products. A new one-dimensional coordination polymer, catena-poly[[[bis{1-[(1H-benzimidazol-2-yl)methyl]-1H-tetrazole-κN(3)}zinc(II)]-μ-hexane-1,6-dicarboxylato-κ(4)O(1),O(1'):O(6),O(6')] monohydrate], {[Zn(C6H8O4)(C9H8N6)2]·H2O}n, has been synthesized by the reaction of Zn(Ac)2 (Ac is acetate) with 1-[(1H-benzimidazol-2-yl)methyl]-1H-tetrazole (bimt) and adipic acid (H2adi) at room temperature...
December 1, 2016: Acta Crystallographica. Section C, Structural Chemistry
Pattiya Krinchampa, Kittipong Chainok, Siriporn Phengthaisong, Sujittra Youngme, Filip Kielar, Nanthawat Wannarit
One of most interesting systems of coordination polymers constructed from the first-row transition metals is the porous Zn(II) coordination polymer system, but the numbers of such polymers containing N-donor linkers are still limited. The title double-chain-like Zn(II) coordination polymer, [Ag2Zn(CN)4(C10H10N2)2]n, presents a one-dimensional linear coordination polymer structure in which Zn(II) ions are linked by bridging anionic dicyanidoargentate(I) units along the crystallographic b axis and each Zn(II) ion is additionally coordinated by a terminal dicyanidoargentate(I) unit and two terminal 1-benzyl-1H-imidazole (BZI) ligands, giving a five-coordinated Zn(II) ion...
December 1, 2016: Acta Crystallographica. Section C, Structural Chemistry
Yufeng Wang, Yuwei Gu, Eric G Keeler, Jiwon V Park, Robert G Griffin, Jeremiah A Johnson
We report star polymer metal-organic cage (polyMOC) materials whose structures, mechanical properties, functionalities, and dynamics can all be precisely tailored through a simple three-component assembly strategy. The star polyMOC network is composed of tetra-arm star polymers functionalized with ligands on the chain ends, small molecule ligands, and palladium ions; polyMOCs are formed via metal-ligand coordination and thermal annealing. The ratio of small molecule ligands to polymer-bound ligands determines the connectivity of the MOC junctions and the network structure...
December 5, 2016: Angewandte Chemie
Jeongjae Lee, Ieuan D Seymour, Andrew J Pell, Siân E Dutton, Clare P Grey
Rechargeable battery systems based on Mg-ion chemistries are generating significant interest as potential alternatives to Li-ion batteries. Despite the wealth of local structural information that could potentially be gained from Nuclear Magnetic Resonance (NMR) experiments of Mg-ion battery materials, systematic (25)Mg solid-state NMR studies have been scarce due to the low natural abundance, low gyromagnetic ratio, and significant quadrupole moment of (25)Mg (I = 5/2). This work reports a combined experimental (25)Mg NMR and first principles density functional theory (DFT) study of paramagnetic Mg transition metal oxide systems Mg6MnO8 and MgCr2O4 that serve as model systems for Mg-ion battery cathode materials...
December 5, 2016: Physical Chemistry Chemical Physics: PCCP
Naoto Kuwamura, Yoshinari Kurioka, Takumi Konno
Stepwise construction of a 1D heterotrimetallic coordination polymer containing all three group 10 metal ions via an ammineplatinum(ii) metalloligand with d-penicillamine is reported. This system showed a significant enhancement in heterogeneous catalytic activity for electrochemical hydrogen evolution by the stepwise introduction of Pd(II) and Ni(II) into the Pt(II) metalloligand.
December 5, 2016: Chemical Communications: Chem Comm
Q Muhammad Imran, Noreen Falak, Adil Hussain, Bong-Gyu Mun, Arti Sharma, Sang-Uk Lee, Kyung-Min Kim, Byung-Wook Yun
Exposure of plants to different biotic and abiotic stress condition instigates significant change in the cellular redox status; resulting in the elevation of reactive nitrogen species that play signaling role in mediating defense responses. Heavy metal associated (HMA) domain containing genes are required for spatio-temporal transportation of metal ions that bind with various enzymes and co-factors within the cell. To uncover the underlying mechanisms mediated by AtHMA genes, we identified 14 Arabidopsis HMA genes that were differentially expressed in response to nitrosative stress through RNA-seq analysis...
2016: Frontiers in Plant Science
Zhaohua Dai
Nitrogen-containing pyridine and quinoline are outstanding platforms on which excellent ionophores and sensors for metal ions can be built. Steric and stereochemical effects can be used to modulate the affinity and selectivity of such ligands toward different metal ions on the coordination chemistry front. On the signal transduction front, such effects can also be used to modulate optical responses of these ligands in metal sensing systems. In this review, steric modulation of achiral ligands and stereochemical modulation in chiral ligands, especially ionophores and sensors for zinc, copper, silver, and mercury, are examined using published structural and spectral data...
December 1, 2016: Molecules: a Journal of Synthetic Chemistry and Natural Product Chemistry
Juan Frau, Francisco Muñoz, Daniel Glossman-Mitnik
The chemical reactivity of resveratrol isomers with the potential to play a role as inhibitors of the nonenzymatic glycation of amino acids and proteins, both acting as antioxidants and as chelating agents for metallic ions such as Cu, Al and Fe, have been studied by resorting to the latest family of Minnesota density functionals. The chemical reactivity descriptors have been calculated through Molecular Electron Density Theory encompassing Conceptual DFT. The active sites for nucleophilic and electrophilic attacks have been chosen by relating them to the Fukui function indices, the dual descriptor f ( 2 ) ( r ) and the electrophilic and nucleophilic Parr functions...
December 1, 2016: Molecules: a Journal of Synthetic Chemistry and Natural Product Chemistry
Edurne S Larrea, Roberto Fernández de Luis, María I Arriortua
The {Cu(NO₃)(H₂O)}(HTae)(4,4'-Bpy) (H₂Tae = 1,1,2,2-tetraacetylethane, 4,4'-Bpy = 4,4'-Dipyridyl) 1D coordination polymer has been obtained by slow evaporation. The crystal structure consists of parallel and oblique {Cu(HTae)(4,4'-Bpy)} zig-zag metal-organic chains stacked along the [100] crystallographic direction. Copper(II) ions are in octahedral coordination environment linked to two nitrogen atoms of two bridging 4,4'-Bpy and to two oxygen atoms of one HTae molecule in the equatorial plane. The occupation of the axial positions varies from one copper atom to another, with different combinations of water molecules and nitrate anions, giving rise to a commensurate super-structure...
December 1, 2016: Molecules: a Journal of Synthetic Chemistry and Natural Product Chemistry
Ja Young Cheon, Won Ho Park
This articles reports a simple and green method for preparing uniform silver nanoparticles (AgNPs), for which self-polymerized 3,4-dihydroxy-l-phenylalanine (polyDOPA) is used as the reducing and stabilizing agent in aqueous media. The AgNPs functionalized by polyDOPA were analyzed by UV-Vis spectroscopy, high-resolution transmission electron microscopy (HR-TEM), Fourier transform infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA), Raman spectrophotometry, and X-ray diffraction (XRD) techniques...
November 30, 2016: International Journal of Molecular Sciences
Yu Pan, Yanglu Pan, Junpeng Zhai, Yan Xiong, Jinhua Li, Xiaobing Du, Chenggang Su, Xingguo Zhang
We identified a novel member of the metallothionein (MT) family, Cucumis sativus metallothionein-like 2 (CsMTL2), by screening a young cucumber fruit complementary DNA (cDNA) library. The CsMTL2 encodes a putative 77-amino acid Class II MT protein that contains two cysteine (Cys)-rich domains separated by a Cys-free spacer region. We found that CsMTL2 expression was regulated by metal stress and was specifically induced by Cd(2+) treatment. We investigated the metal-binding characteristics of CsMTL2 and its possible role in the homeostasis and/or detoxification of metals by heterologous overexpression in Escherichia coli cells...
November 30, 2016: Genes
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